The rule looks like the following: when science becomes a matter of public health, politics steps in, kills off the scientific debate, stifles independent research and opts for the (politically) safest option, that is (a) likely to be an oversimplification (effects taken as causes), (b) unlikely to be the best choice by a long shot, and (c) likely to be centered around people having to change their behaviors and just lead a more saintly life (eat bland food against cholesterol, avoid stress against stomach ulcer, burn less coal against climate change, stop using DDT against malaria-carrying mosquitos, or whatever else).

The end result is millions of people feeling the guilt of having brought ill health to themselves (or left almost powerless against diseases, in the case of DDT and ulcers), despite there being no actual good reason whatsoever.

Their underlying problems may or many not be managed but are never solved, and their lives are un-necessarily ruined.